Lung cancer is currently the leading cause of cancer death in both men and women in Europe, with an estimated 250000 new cases diagnosed in 2005. The continued poor outcome of patients indicates that the current recommended regimens are falling short. In addition, many of the commonly used chemotherapy agents are associated with severe nonhematologic toxicities that are often cumulative and nonreversible and impair quality of life in this essentially palliative setting. Therefore, agents with novel mechanisms of action and superior safety profiles need to be investigated. More than 50% of lung cancer shows carcinoembryonic antigen (CEA) expression and anti-CEA radioimmunotherapy (RAIT) could be used. The investigators group showed that pretargeted RAIT (PRAIT) using bispecific antibody (bsMAb) can deliver a higher radiation dose to a tumor than a directly radiolabeled anti-CEA antibody, and shows improved anti-tumor efficacy. This clinical trial is designed to assess PRAIT using an entirely new recombinant anti-CEA bsMAb and a 177Lu-labeled peptide for the treatment of CEA-expressing small cell lung cancers (SCLC) or CEA-expressing Non Small Cell Lung Carcinoma (NSCLC)